CHEMOSPHERE
·
2023
·
IF 8.8
Zejun Wang,Zhibing Yang,Yi-Feng Chen
Surfactant-enhanced aquifer remediation has been proved successful to remove dense non-aqueous phase liquids (DNAPLs) from contaminated sites. However, the underlying mechanisms of the DNAPL mobilization and solubilization at the pore scale remains to be addressed for efficient application to the field remediation system. In this work, the emerging microfluidic and imaging technologies are applied to investigate the dynamics of DNAPL remediation. Visualized experiments of the evolution of DNAPL remediation are performed to study the role of surfactant type, concentration and injection rate. The DNAPL remediation is dominated by mobilization followed by solubilization for most surfactants. Mobilization occurs as soon as surfactants and DNAPL are in contact until forming a new stable phase structure, and the solubilization continues until the end of injection. We observe the breakup behavior of long droplets and ganglia during the mobilization, which is attributed to the surfactant-reduced interfacial tension and thus expedites DNAPL mobilization and redistribution. During the solubilization, the formation of micelles incorporating DNAPL fractions increases the DNAPL concentration gradient and thus enhances the mass transfer, but the rate-limited diffusion of micelles reduces the mass transfer rate coefficient. Increasing the surfactant content and decreasing the injection rate can promote mobilization and solubilization. The DNAPL mobilization ability of the surfactants SDS and SDBS is stronger than SAOS and Tween 80 regardless of the injection rates. Tween 80 may be considered an ideal surfactant of only solubilization but not mobilization is desired. This work elucidates the pore-scale mechanisms during surfactant-enhanced DNAPL remediation, which are beneficial for upscaling studies, predictive modeling, and operation optimization of DNAPL remediation in the field.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MATERIALS & DESIGN
·
2025
·
IF 7.9
Mengjiao Jiao,Yang Zhang,Guishang Pei,Zhuoyang Li,Xuewei Lv
This study focused on the high-temperature phase equilibrium of the Fe 2 O 3 -TiO 2 system by employing the classic phase equilibration and quenching method, X-ray diffraction, electron-probe microanalysis, and thermal analysis experiments. The solubility of the hematite, pseudobrookite, and rutile phases as the equilibrium temperature rose from 1100 °C to 1450 °C was determined. Besides, the solubility of TiO 2 in the spinel phase at 1450 °C was verified by experiments. A comprehensive comparison with the phase diagram optimized by Panda indicates that the solubility of solid solutions involved in the Fe 2 O 3 -TiO 2 system should be larger than the predicted one. Additionally, the ordered rutile phase was transformed into the high-temperature rutile-derived crystallographic shear structure at 1400 °C with Fe 2 O 3 higher than 15 mol%. Furthermore, the eutectic reaction of liquid → pseudobrookite + rutile occurred at 1512 °C. The liquidus was determined to be 1512 °C and 1535 °C at 30 and 75 mol% of TiO 2 , respectively. These measured phase equilibrium data are expected to provide reliable input for future thermodynamic reassessments of the Fe 2 O 3 -TiO 2 system within the CALPHAD framework.
研究领域:
材料科学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Lili Huo,Guansheng Liu,Yan Li,Xin Yang,Hua Zhong
One-dimensional flow column experiments are conducted to specifically compare the transport behavior of three surfactants (sodium dodecyl benzene sulfonate (SDBS), Triton X-100, rhamnolipid) and a solvent n-propanol and their solubilization on dodecane in porous media . Compared to pentafluorobenzoic acid (PFBA), the low adsorption or partition loss of n-propanol incurred no retardation, shouldering or retention in breakthrough curves. While for surfactants, all the breakthrough curves exhibited retardation, shouldering or retention to different degrees in the presence of dodecane phase. Compared to the anionic SDBS with no significant bulk partition to non-aqueous phase liquid (NAPL), the non-ionic Triton X-100 with partition induced significant retardation and shouldering in breakthrough curves. The retention loss of solubilized aggregates resulted in obvious retention of rhamnolipid at different pore-water velocities. The increase of pore-water velocity could promote the transport of surfactants and the dodecane-surfactant aggregates. The elution of dodecane in the presence of surfactants showed a significant relation to the partition behaviors of surfactants and a characteristic of the rate-limited solubilization. In contrast, the n-propanol, which is basically a non-reactive solvent, exhibited the rapid equilibrium dissolution of dodecane. The results indicated that in remediation of field sites contaminated by hydrophobic organic contaminants (HOCs), the surfactants should be rationally selected, and a favorable pore-water velocity should be used to obtain a high remediation efficiency and to reduce the retention loss of surfactants as well.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2019
·Vol. 7
·期 19
·1900491
·
IF 7.125
Lixiao Yin,Haodi Wu,Weicheng Pan,Bo Yang,Penghua Li,Jiajun Luo,Guangda Niu,Jiang Tang
Cs 2 AgBiBr 6 double perovskite recently emerges as a promising semiconductor for ionization detections because of the low detection limit and nontoxic composition. However, it suffers from unsatisfactory reproducibility and wide fluctuation of electrical properties, as also in other halide perovskite systems. Here, solubility and supersolubility are employed as quantitative indicators to direct the growth of Cs 2 AgBiBr 6 single crystals. The optimized Cs 2 AgBiBr 6 crystals exhibit smooth surface as well as high resistivity with narrow distribution from 6.10 × 10 9 to 3.31 × 10 10 Ω cm, in contrast to the unoptimized Cs 2 AgBiBr 6 crystals ranging from 6.04 × 10 7 to 5.61 × 10 9 Ω cm. Moreover, the fabricated X-ray detector has a sensitivity of 1974 µC Gy air −1 cm −2 under 50 V mm −1 electric field, which is close to lead halide perovskite detectors. This study highlights the importance of quantitative understanding about the growth process, and might also be applicable to other crystal growth methods, for instance, antisolvent or solvent evaporation method.
研究领域:
材料科学
·
半导体物理
·
晶体生长
✓ 已验证
产品关联
DOI
高影响因子
POLYCYCLIC AROMATIC COMPOUNDS
·
2016
·
IF 0.959
Jian Long,Senlin Tian,Yanhua Niu,Yueming Jin,Lin Li
Reduplicate utilization of surfactants is a key factor for Surfactant-Enhanced Remediation (SER) technology to reduce its high operation costs. In order to achieve the reuse of surfactants, this study attempted to construct a novel reversible solubilization system for SER. Three typical polycyclic aromatic hydrocarbons (PAHs) pyrene, phenanthrene, and acenaphthene were controllably solubilized and released by the mixed micelles composed of redox-active cationic surfactant (11-Ferrocenylundecyl) trimethylammoniunm bromide (FTMA) and conventional nonionic surfactant Tween80. Solubilization of PAHs is assumed to be controlled by changing the redox states of FTMA. Cyclic voltammograms tests of FTMA showed the oxidation and reduction potential were 0.4570 and 0.4068 V, respectively, and the peak currents ratio of FTMA and FTMA+ was 1.26, verified that FTMA possesses electrochemically reversible property. In FTMA-Tween80 mixed solutions, CMC values demonstrated the nonideal interaction between the two surfactants and the interaction parameters (β) was -5.5296 when the mass ratio was FTMA:Tween80 = 2:8. Due to the synergistic solubilization effect, the apparent water solubilities of PAHs were significantly enhanced by the mixed surfactant, and they were much higher than those in single surfactant. After oxidation, more than 50% of the PAHs in mixed micelles could be released, the cumulative release efficiency of selected PAHs followed the order of pyrene > pherantherene > acenaphthene. Briefly, such results in this article provide a facile method to meliorate the SER technology.
研究领域:
环境科学
·
电化学
·
污染修复
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）